In my application referenced above, two cranks are journaled from opposite directions into independently operating friction brakes, all operationally secured within a central housing. The friction brakes of each crank are adjusted as to friction bias, by a common frictional biasing means that includes an activation rod that extends exterior of the housing. But since the rod is disposed coaxial of the axes of rotation of the assembly, it must extend through the hub of one of the crank. In addition, in such extension position, the rod can be fitted with a handle which is positioned adjacent to the plane of rotation of the crank handle. In such position, the rod handle has been found to sometimes interfere with one of the user's arms as the cranks are worked.